Master cylinder conversion

[karl]

I have a 75 half c10. I want to convert to the 81 and up master cylinder. Do the tops on these seal better then the cast iron crap. I like the idea of a see through res and aluminum housing but not sure about the lids? Probably better if screw lid.

[USSkoval]

My cast iron ones seal just fine?

[karl]

Ive had problems with them. I opened mine up the other day and the back was bone dry. Wouldnt have happened if i could see through. Now i have to bleed the system. I take the lid off and fluid spills and splatters all over. A mess. Rust inside. Got to be a better way. Must be a reason why they upgraded them in 81.

[USSkoval]

If it was bone dry, I would be looking for a leak elsewhere. It being empty could also cause the rust in there.

Visibility may not be the real reason they switched, it was likely cost.

[menace121978]

i'm looking to do the same. i hate the cast iron. i'm almost positive mc off an 84-86 will work. i say almost because i haven't do it yet. very soon though

[karl]

I had an 85 nissan 720 pu with a master cylinder much like the 81 c10. Alum housing and plastic res. Never in the 21 yrs i drove that truck did i have to replace that master cylinder. I rebuilt it once. No problems. The cast iron one on my c10 has been there 2 yrs and it looks rusty and crusty inside and out. Anything painted around it is rusty too as a result of this poor design. Every time i pop the top, fluid spills from the rubber pc. No more of these cast iron jokes.